Memory system and assembling method of memory system
According to one embodiment, each memory chip included in a memory package includes a first storage unit that stores therein first information that is n-bit information and is a comparison target of a chip address, and is used for identifying its own memory chip, a second storage unit that stores therein second information for determining an effective bit of the n-bit first information, and a control unit that determines an effective bit of the n-bit first information and an effective bit of the chip address based on the second information.
1. A memory system comprising:
a memory package including a plurality of memory chips, each of the memory chips including a non-volatile memory cell array; and
a controller configured to select one memory chip from the memory package based on a chip enable and a chip address, wherein
each of the memory chips includes
a first storage unit configured to store therein first information that is n-bit information (n is an integer of 2 or more) compared to the chip address, the first information being used for identifying its own memory chip,
a second storage unit configured to store therein second information for determining an effective bit of the n-bit first information, and
a control unit configured to determine an effective bit of the n-bit first information and an effective bit of the chip address based on the second information.
2. The memory system according to claim 1 , wherein the first information has a bit number capable of identifying the plurality of memory chips up to a predetermined number of memory chips.
3. The memory system according to claim 1 , wherein at a time of start-up, the control unit is configured to read the first and second information stored in a memory cell array area of each memory chip to store the first and second information into the first and second storage units.
4. The memory system according to claim 1 , wherein at a time of start-up, the controller is configured to transmit a command for setting the second information in the second storage unit to the memory package.
5. The memory system according to claim 4 , wherein the command is a broadcast command and is transmitted to the memory chips within the memory package at a same time.
6. The memory system according to claim 1 , wherein when the control unit outputs a value of third information that indicates a storage capacity per chip enable to the controller, the control unit is configured to output a different value of the third information corresponding to a plurality of different values of the second information.
7. The memory system according to claim 1 , wherein the control unit, when the effective bit of the n-bit first information is identical with the effective bit of the chip address and when the chip enable is asserted, determines that own memory chip is selected.
8. A memory package including a plurality of memory chips, each of the memory chips including a non-volatile memory cell array, wherein
each of the memory chips includes
a first storage unit configured to store therein first information that is n-bit information (n is an integer of 2 or more) compared to the chip address, the first information being used for identifying its own memory chip,
a second storage unit configured to store therein second information for determining an effective bit of the n-bit first information, and
a control unit configured to determine an effective bit of the n-bit first information and an effective bit of the chip address based on the second information.
9. The memory package according to claim 8 , wherein the control unit, when the effective bit of the n-bit first information is identical with the effective bit of the chip address and when the chip enable is asserted, determines that own memory chip is selected.
10. The memory package according to claim 8 , wherein the first information has a bit number capable of identifying the plurality of memory chips up to a predetermined number of memory chips.
11. The memory package according to claim 8 , wherein at a time of start-up, the control unit is configured to read the first and second information stored in a memory cell array area of each memory chip to store the first and second information into the first and second storage units.
12. The memory package according to claim 8 , wherein when the control unit outputs a value of third information that indicates a storage capacity per chip enable to a controller, the control unit is configured to output a different value of the third information corresponding to a plurality of different values of the second information.
13. An assembling method of a memory system that assembles a memory package and a controller, the memory package including a plurality of memory chips, each of the memory chips including a non-volatile memory cell array, the controller selecting one memory chip from the memory package based on a chip enable and a chip address, the assembling method comprising:
changing of second information that is stored in the non-volatile memory cell array, the second information being used for determining an effective bit of n-bit first information (n is an integer of 2 or more), the n-bit first information being a comparison target of the chip address; and
connecting a chip enable pin of the controller to a chip enable pin of the memory package by wires corresponding to the changing of the second information.
14. The assembling method according to claim 13 , further comprising:
not changing the first information, when the second information being changed.